A remote-control system is known from WO 2014/041 022 A2 and DE 101 29 189 A1. A remote control system for a crane is known from DE 20 2006 017 719 U1 and EP 2 489 625 A1. For the purpose of operating the remote-control system a special operating unit is required which, in particular, is matched to the machine to be operated.